Product Details

Techfilter
Anti-Aliasing Filter Card
 

ELIMINATE ALIASES The Techfilter is a high performance, 16 channel, analogue low pass filter designed for PC compatible based signal acquisition systems. Low pass filters are required in front of analogue-to-digital convertors to prevent aliasing of high frequency components into your resultant output.
If left unfiltered, these components (which may be nothing more than noise) will “fold down” causing gross errors in your results. By setting the cutoff frequency of the Techfilter to below the Nyquist frequency, the Aliasing problem is eliminated. 700 incremental cutoff frequency steps are available to allow precise setting of the filter to match the sampling rate of your ADC.

PC BASED The Techfilter is built to a standard 4 1/211 x 1 3” PC standard size which will fit any standard IBM/PC AT single card slot. It acts as a front end for your own A-to-D convertors, conditioning the signals before they get to the A-to-D card. Because it includes programmable gain up to 1000 and differential to single ended conversion, it can significantly improve the performance and flexibility of your signal acquisition cards.
All functions are software controlled by simple to use utility programmes supplied with each card. The Techfilter is addressed directly though the XT/AT bus eliminating the need for any external connections. Just plug-in, switch on, set the configuration and Go!

 

Software Features:
Independant Channel Control	Differential or single ended inputs. Gain of 1, 10, 100 or 1000. AC or DC coupling Filter or bypass mode
Cutoff Frequency	Software programmable 1 Hz to 250 Hz in 1Hz steps 2.5 KHz to 25 KHz in 100 Hz steps
Computer Interface	Supplied with 'pop-up' window configuration software for setting corner frequencies and all other functions. Runs under MSDOS on PC's. Fortran and 'C' callable files also included.

 

Techfilter Data

General

Input voltage ± 5V Input impedance 1M ohm Gain accuracy ± 1% Input offset (trimmable) 0.2 mV max Input noise 0.6 mV rms CMRR @ G = 1000 115dB typical Channel crosstalk <80 dB Output Impedance 10 K ohm Output voltage ± 5 V Power 1.5 W max

Filter

16 channel low-pass elliptical filter with 7 poles, 6 zeros. Rolloff 70 dB/octave Corner frequency accuracy ± 0.5% Pass band ripple ± 0.1 dB Stopband attenuation 70 dB min Clock breakthrough @ 100 x fc 5mV rms max Phase difference between channels ± 2 deg max Total harmonic distortion 0.1% max

 

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Revised: October 28, 1999
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